1. Field of the Invention
The present invention relates to a display device. More specifically, the present invention relates to a display device with which a leg extension and retraction function that allows the effective length of the leg of a stand unit to be increased or decreased is imparted to a stand unit for supporting a main display component in a tilted orientation.
2. Background Information
In the past, it has been proposed that a main display component having a forward-facing display screen can be tilted by attaching a stand unit to this main display component. This arrangement allows the effective length of the leg of the stand unit to be adjusted to either of two stages, and allows the leg to be stored on the back of the main display component, and pulled out from the back of the main display component (see Japanese Utility Model Registration 2,096,746 and Japanese Laid-Open Patent Application 2005-6057, for example). The structure of a stand unit A used in such a conventional display device will be briefly described through reference to FIGS. 7 and 8.
This stand unit A has an attachment base 100 affixed to the back of a main display component (not shown), and a case 1 in the shape of a flat box is pivotably attached to this attachment base 100 via left and right lateral shafts 110. This case 1 is designed to be positioned in one of two positions, a storage position in which it is stowed in a recess 120 of the attachment base 100, and a working position in which it is pulled out diagonally downward from this recess 120, by the action of a positioning mechanism, which does not appear in the drawings. With the stand unit A shown in FIGS. 7 and 8, the flat box-shaped case 1 is formed by screwing a fitted cover (not shown) to a case body 12, using screw holes made in the required places of the case body 12. Accordingly, for the sake of convenience, the number 12 indicating the case body and the number 1 indicating the case are both shown in FIGS. 7 and 8.
The stand unit A has a leg 3, and a slider 2 that is affixed to the upper end of this leg 3 is housed in the case 1 so as to be capable of sliding up and down. The case 1 is equipped with a slider position restriction means 5, and the action of this slider position restriction means 5 restricts the slider 2 to two positions in the case 1, namely, an upper position (see FIG. 7) and a lower position (see FIG. 8). This slider position restriction means 5 is constituted by a cam component 6 in which an upper latching component 61 of an upper end and a lower latching component 62 of a lower end are linked by a flat face 63, and a spring 7 that is a leaf spring equipped with an engagement component 71 that allows the upper latching component 61 and the lower latching component 62 to be selectively latched. The engagement component 71 is formed by the apex of a peaked portion formed in the spring 7. The cam component 6 is provided on the slider 2 side, and the spring 7 is provided on the case 1 side.
When the slider 2 is moved upward as indicated by the arrow Y1 in FIG. 7, so that the lower latching component 62 of the cam component 6 is latched to the engagement component 71, the protrusion length (that is, the effective length) of the leg 3 from the case 1 is shortened. Therefore, when the case 1 is pushed into its storage position in this state, the overall length portion of the leg 3 is also stored in the back of the main display component (not shown). In contrast, the effective length of the leg 3 from the case 1 is lengthened when the case 1 is pulled out from its storage position to its working position, and the slider 2 is moved downward as indicated by the arrow Y2 in FIG. 8 so that the upper latching component 61 of the cam component 6 is latched to the engagement component 71. In this case, if the leg 3 and the lower end of the main display component (not shown) are set on the floor, etc., the main display component will be supported in a tilted orientation by the leg 3.
It has also been proposed that the tilt angle of a display device can be made variable by providing a display device with a fixed leg and a movable leg, and varying the tilt angle of the movable leg (see Japanese Laid-Open Utility Model Application S61-19293, for example). With the device of Japanese Laid-Open Utility Model Application S61-19293, the tilt angle of the movable leg is made continuously variable by using a gear or a stopper member.
With the conventional stand unit A described through reference to FIGS. 7 and 8, when the main display component is supported in a tilted orientation by the leg 3 whose effective length has been increased by moving the slider 2 downward as indicated by the arrow Y2 in FIG. 8, the load produced by the weight of the main display component, etc., is received by the upper latching component 61 of the cam component 6 via the engagement component 71 formed by the apex of the peaked portion of the spring 7. Accordingly, for the main display component to be stably supported by the stand unit A in a tilted orientation, the spring 7 needs to have enough elasticity so that the engagement component 71 will remain latched to the upper latching component 61, and not retract, even if the upper latching component 61 of the cam component 6 is pushed on by the engagement component 71 of the spring 7.
Conversely, when the effective length of the leg 3 is to be increased, the leg 3 is pulled out by hand, the result being that the lower latching component 62 of the cam component 6, which is latched to the engagement component 71 of the spring 7 as shown in FIG. 7, is removed from the engagement component 71, and then the flat face 63 of the cam component 6 is slid over the engagement component 71, and the upper latching component 61 of the cam component 6 is latched to the engagement component 71 as shown in FIG. 8. When the effective length of the leg 3 is to be shortened, the leg 3 is pushed in by hand, the result being that the upper latching component 61 of the cam component 6, which is latched to the engagement component 71 as shown in FIG. 8, is removed from the engagement component 71, and then the flat face 63 of the cam component 6 is slid over the engagement component 71, and the lower latching component 62 of the cam component 6 is latched to the engagement component 71 as shown in FIG. 7. Therefore the spring 7 only needs to have enough elasticity to allow the above operations to be carried out.
Because of this, with a display device that makes use of this stand unit A, the elasticity of the spring 7 must be kept low enough that when the leg 3 is pulled out by hand, the lower latching component 62 of the cam component 6 latching the engagement component 71 can ride up and over while the engagement component 71 of the spring 7 is retracted, and must be kept low enough that when the leg 3 is pushed in by hand, the upper latching component 61 of the cam component 6 latching the engagement component 71 can ride up and over while the engagement component 71 is retracted, but on the other hand, must be kept high enough that the upper latching component 61 of the cam component 6 does not come off from the engagement component 71 of the spring 7 when the main display component is supported in a tilted orientation. Conversely, if the elasticity of the spring 7 is too high, it will be impossible to increase the effective length of the leg 3 when it is pulled out by hand, or to decrease its effective length when it is pushed in by hand.
However, as in these conventional examples, when the elasticity of the spring 7 of the stand unit A is set such that the effective length of the leg 3 can be increased by pulling out the leg 3 by hand, or can be shortened by pushing in the leg 3 by hand, and such that the main display component can be supported in a tilted orientation, if the main display component disposed in a tilted orientation becomes larger and heavier, or if some kind of external pressing force is exerted on a main display component disposed in a tilted orientation, then there is the danger that too high a load will be applied to the engagement component 71 of the spring 7 latched by the upper latching component 61 of the cam component 6 as shown in FIG. 8, and that as a result the engagement component 71 will come off from the upper latching component 61 of the cam component 6.
If this should happen when the main display component is being supported in a tilted orientation by the stand unit A, since the flat face 63 of the cam component 6 will readily slide the engagement component 71 of the spring 7, the leg 3 may be pushed in and its effective length shortened too much, and as a result, the main display component may fall over backwards. More specifically, the leg 3 may be pushed in and the main display component fall over backwards if the main display component should unintentionally be pushed on while the user is viewing the images on the display screen of the main display component that is set up on the floor in a tilted orientation.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need to provide an improved display device with which measures are taken such that when the elasticity of the spring is set such that the effective length of the leg can be lengthened or shortened by hand and the main display component can be supported in a tilted orientation, there will be no problem of the upper latching component of the cam component coming off from the engagement component of the spring, and the cam component sliding until the leg is pushed all the way in to its storage length, and with which even without changing the elasticity of the spring, it is possible to prevent the problem of a main display component in a tilted orientation collapsing to the rear in the event that the main display component should be large and heavy, or that some kind of external pressing force is exerted on the main display component.
There exists another need to provide an improved display device with which the above-mentioned object can be achieved without modifying the elasticity of the spring, and merely by changing the shape of the cam component, without increasing the number of parts required.
There exists yet another need to provide an improved display device with which measures are taken that allow the elasticity of the spring to be increased or decreased, the result of which is that the action of preventing the upper latching component of the cam component from coming off the engagement component of the spring, and the leg from being pushed in, can be suitably manifested according to the weight of the main display component and other such factors.
This invention addresses these needs in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.